Both ritonavir (RTV) and indinavir (IDV) are approved by the FDA to treat HIV, but IDV has not been approved for use in children and the doses for the combination of the two drugs has not been studied in children. The purpose of this study is to find a combination of RTV and IDV that is safe, well tolerated, and produces drug levels in the blood of children that are comparable to effective drug levels in the blood of adults. The effectiveness of the drug combination in decreasing the amount of virus in the body will also be studied. The children enrolled in this study will have high HIV viral loads despite taking anti-HIV drugs.